The newly posted App Store Review Guidelines contain newly spelled out details on how Apple reviews applications. Urban Airship's tools are always designed to work within Apple's policies, and even to help you follow Apple's rules without extra work on your part.
The two sections that cover our products are "5. Push notifications" and "11. Purchasing and Currencies." We suggest reviewing these guidelines to make sure your application fits within Apple's rules. Also see the Attachment I and II of the iOS Developer Program License Agreement, which have additional details on push notification and in-app purchase guidelines (including the rules governing third party services like Urban Airship).
If you have any questions about specific scenarios, please open a new support ticket.